East Toronto and Midway Overflow Sewer

Construction Details:
Mainly concrete arch. Two tributary arms are 6x8' (Midway) and 6'6"x7'9" (East Toronto), while the main tunnel beneath Coxwell between Dundas and Queen is 8'x9'3". South of Queen, 2xRCB 2640x1800 was added in the 1940s.

The East Toronto and Midway Overflow provides an overflow route for two significant combined sewers, the Midway sewer and the East Toronto sewer, along with some smaller combined pipes. It also takes stormwater from a modern RCP running beneath Coxwell Avenue, and has a vertical connection to another storm sewer that runs west of the old Main treatment plant site. This vertical shaft may provide additional overflow relief for the Midway arm.

After annexing Midway, Norway Village and East Toronto in 1908-1909, the City of Toronto moved to build a new sewage disposal works west of the old Woodbine Racetrack in the area that is now roughly between Lakeshore Blvd. E. and Eastern Avenue, west of Coxwell. The newly annexed villages and suburbs urgently required sewer service of their own, and so two main trunk sewers were installed, the Midway sewer just east of Greenwood Avenue along a north-south alignment, and the East Toronto sewer running south from the Danforth beneath Woodbine Avenue and then west beneath Kingston Road. Small weirs and troughs were installed to divert dry-weather flow in these combined sewers into small pipes that connected either to the end of the High-Level Interceptor (in the case of the Midway sewer) or directly to the Main Treatment Plant. Downstream of these diversions, an overflow sewer allowed wet weather overflows from these combined sewers to flow into Ashbridges Bay.

This overflow sewer consists of two moderate-sized arched concrete conduits that originate at the respective combined sewer diversions and join beneath the intersection of Dundas St. E. at Coxwell. A somewhat larger arched conduit then takes the overflows to about Eastern Avenue, where the original outfall was located. Sometime after 1938 and before 1949, twin rectangular ducts were added to accomodate the filling of the stretch of creek or marsh that separated the Main treatment plant from the racetrack site. The overflow sewer now outfalls into the east side of the much-reduced Ashbridges Bay.

Map of sewer.Photographs are marked with a circle, click to open a popup on the map, click on the ensuing thumbnail to open the full version. All paths and photo locations are approximate.

Michael Cook is available to speak to your organization about infrastructure history, lost creeks, current conditions, and opportunities for change in our management of and communication about urban watersheds, and to work with teams proposing or implementing such change. Get in touch.

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